This invention relates generally to medical devices, and more particularly, to an endovascular stent graft assembly and a delivery device for placement and deployment of the stent graft assembly in a vessel lumen.
Stent grafts may be inserted into an anatomical vessel or duct for various purposes. For example, stent grafts are used for treatment of vasculature in the human or animal body to bypass or repair a defect in the vasculature or to maintain or restore patency in a formerly blocked or constricted passageway. For example, a stent graft may extend proximally and/or distally away from a vascular defect, including a diseased portion such as an aneurysm or dissection, and engage a healthy portion of a vessel wall.
In recent years stent grafts have been developed for treatment of aortic aneurysms and dissections. These devices are delivered to the treatment site through the vascular system of the patient rather than by open surgery. The stent grafts include a tubular or cylindrical framework or scaffolding of one or more stents to which is secured a generally tubular shaped biocompatible graft material such as woven Dacron®, polyester, polytetrafluoroethylene, or the like. The devices are initially reduced to a small diameter and placed into the leading or proximal end of a catheter delivery system. The delivery system is inserted into the vascular system of the patient and maneuvered to the treatment site over a previously positioned guide wire. Through manipulation of a control system that extends along the length of the delivery device to a distal end of the system outside the patient, the stent graft may be deployed at a desired location after withdrawing a surrounding sheath. The stent graft becomes anchored into position to healthy wall tissue in the aorta. The delivery device may then be removed, leaving the stent graft in place and thereby bypassing an aneurysm or dissection in the aorta.
For treatment of thoracic aortic aneurysms and/or dissections in particular, it is necessary to introduce the stent graft high up in the aorta and in a region of the aorta which is curved and where there can be strong blood flow. Furthermore, in the thoracic aorta there are major branch vessels extending therefrom, such as the brachiocephalic, carotid and/or subclavian arteries. During and/or after treatment of an aneurysm or dissection in the region of the thoracic arch, it is desirable for blood supply to continue to flow to these branch arteries. For this purpose, fenestrations or side branches are provided in a stent graft that is placed in that region, through which side arms or branch extensions may be deployed and extend into the brachiocephalic, carotid and/or subclavian arteries, for example.
It has also been recognized that endovascular treatment of diseased vessels can be simplified by use of pre-loaded components such as guide wires, catheters, and/or sheaths. These pre-loaded components can be pre-loaded into a delivery system (e.g., a delivery device or introducer) and/or a prosthetic device (e.g., a stent graft) prior to introduction into a patient to aid in delivery of additional prosthetic devices (e.g., branch extension or side arm prostheses) extending from the main prosthetic device. These pre-loaded components may help to simplify and improve branch vessel cannulation, thereby facilitating accurate placement of a branched stent graft assembly in the aortic arch and descending thoracic aorta and one or more branch arteries extending therefrom.